This car's best attributes are probably the ride and handling. Only the most severe road defects upset the smooth as glass ride and it handles suprisingly well for such a big car. The steering is super light, like the wheel isn't connected to anything. I personally love making one finger u-turns. The brakes aren't so great, don't go that fast (not that you even could) and make sure to leave plenty of stopping distance.
It's exterior styling is a strong point too. I think these are among the best looking Cadillacs. The interior is, as you would expect, very comfortable. My friend's actually fight over who gets to sit in back, they say it's like driving around on your living room couch.
Fuel economy isn't too bad either, about 16 or 17 in the city, about 26 or 27 on the highway. Speaking of highway driving, this car is great on long trips, you just glide along and relax.
And now for performance. The car well, uh, moves under its own power. It's not so slow that you will get killed trying to merge onto a highway, but don't even try to race anyone, you'll embarass yourself. The HT 4100, for all the horror stories you may have heard, has been trouble free in my car.